The purpose of this study is to determine the prevalence of impaired glucose (carbohydrate) tolerance in lean children with a family history of diabetes and in overweight/obese children with or without a family history of diabetes mellitus.

The patient participates in the study for a total duration of approximately four hours. The study nurse will do a nursing assessment, including measuring the patient's height, weight, waist circumference, hip circumference, blood pressure, and pulse, along with evaluation of acanthosis nigricans and striae rubrae. The patient's percent body fat, fat mass and lean mass may also be measured using a Tanita scale. The nurse will obtain a family and medical history from the patient and/or the patient's parent/guardian. In addition, before starting the oral glucose tolerance test (OGTT), the nurse will request a urine sample from the patient for analysis of microalbumin and creatinine.

The patient will receive 1.75 g/kg to a maximum of 75 g of a sugar drink, orally (Glucola). The patient will have one intravenous line. "Emla" or a local anesthetic (0.1cc buffered lidocaine) will be applied before the placement of the IV catheter. Blood will be drawn 10 times over three hours. Should abnormal glucose results be found, appropriate referrals will be made. We will draw approximately 80 cc of blood during this study. The blood will be analyzed for glucose, lactate, insulin, proinsulin, c-peptide, interleukin-6, tumor necrosis factor-α(TNF), free fatty acids (FFAs), enhanced lipid profile, leptin, and adiponectin as well as an optional 10 cc sample to be stored for future undetermined analysis.

Inclusion Criteria:

• ages 7-21
• family history of type 2 diabetes mellitus

Exclusion Criteria:

• Children will be excluded if they have previously been treated for another endocrinopathy or are on any chronic medications that are known to alter glucose or insulin metabolism, such as oral steroids, or certain psychiatric medications, such as Xeleca, Lithium and Paxil.
• Lean (not overweight or obese) will be defined as a body mass index (BMI) (kg/m2) less than the 85th percentile specific for age and gender, overweight will be defined as a BMI between the 85th and 95th percentiles, and obesity will be defined as a BMI greater than the 95th percentile.
• Children will be excluded from participating in the genetic analysis if they are treated oral glucocorticoids or antirejection or chemotherapy (e.g. tacrolimus, Lasparaginase.

Primarily these patients are recruited from Yale Pediatric Endocrinology Clinic or are siblings of patients.